SCIURUS. 109 
Color. Above gray, as are also the sides; outer surface of limbs 
pale gray; rest of pelage white; orbital ring grayish white; ears 
grayish; tail above black and white mixed, fringed on sides with 
white, beneath cinnamon rufous. 
Measurements. Total length (skin), 260-304; tail vertebre, 254- 
287; ear: height, 23-25; width at base, 21.5-24. Skull: average of 
five; basilar length, 55.5; palatal length, 28.4; interorbital width, 37.1; 
length of upper molar series, 11.7. 
77. arizonensis (Sciurus), Coues, Am. Nat., 1867, p. 357. Elliot, 
Syn. N. Am. Mamm., 1901, p. 59. 
coli@i Allen, Mon. N. Am. Rod., 1877, p. 738. (nec Rich.) 
ARIZONA GRAY SQUIRREL. 
Type locality. Fort Whipple, Yavapai County, Arizona. 
Geogr. Distr. State of Nuevo Leon, Mexico (San Pedro Mines, 
Allen), to Arizona. Texas? 
Genl. Char. Smaller than S. carolinensis; tail as long as head and 
body; soles naked to heel. 
Color. Above mixed gray, black, white, and tawny, the latter 
predominating; sides and limbs outside grizzled gray and white; 
beneath and inside of limbs pure white; tail above basally gray and 
white, remainder black mixed with white and fringed broadly with 
white, beneath tawny in the center, bordered with black and fringed 
with white. 
Measurements. Total length, 457.4; tail vertebre, 241.3; hind 
foot, 58.4; height of ear, 20.3. Skull: occipito-nasal length, 63; 
Hensel, 48; zygomatic width, 35; interorbital width, 20; palatal 
length, 21; length of upper molar series, 11. 
a.—huachuca (Scturus), Allen, Bull. Am. Mus. Nat. Hist., 1894, 
p. 349. Elliot, Syn. N. Am. Mamm., roor, p. 60. 
HvuACHUCA SQUIRREL. 
Type locality. Huachuca Mountains, southern Arizona. 
Geogr. Distr. Huachuca Mountains, Arizona, into State of Sonora, 
Mexico. 
Genl. Char. Similar to S. arizonensis, but nearly uniform gray 
above, only a trace of fulvous dorsal stripe. 
Color. Upper parts grizzled gray; dorsal stripe nearly obsolete; 
sides lighter gray; nape patch pale fulvous; under parts of body and 
limbs pure white; tail above black sprinkled with white and fringed 
broadly with white, beneath pale chestnut, bordered with black and 
broadly fringed with white. 
Measurements. Total length, 540; tail vertebra, 265; hind foot, 
70;ear, 34. Skull: average of four; basal length, 53.5; palatal length, 
